This invention relates to medical simulators. The invention is particularly concerned with the provision of a medical simulator designed to teach and to refine the psychomotor skills associated with the medical procedures of administering regional and local anesthetic and analgesic agents.
The particular form of medical simulator hereinafter described is designed specifically for the use by medical personnel learning or refining the skills of regional anesthesia. Further it is particularly designed for those procedures where observing the reaction of the nervous system to electrical stimulation allows for accurate placement of anesthesia or analgesic agents.
The invention also relates to simulation systems designed to simulate any procedure that requires any device that is conductive to puncture the skin or enter the body through a natural or unnatural orifice, e.g., brachytherapy. The invention is further not limited to simulation of human anatomy, i.e., veterinary procedures can be supported.
The procedure of regional anesthesia involves knowledge of the anatomy of the relevant parts of the human nervous system, the response of the human nervous system to either direct pressure or electrical stimulation and the pharmacology of local anesthesia. Further, recent techniques also require familiarity with electrical equipment that produces a controllable current at the tip of a surgical needle so that specific parts of the nervous system can be stimulated.
The techniques associated with administering anesthesia are extremely difficult to learn and to perform. These techniques require the anaesthetist to recognize the tactile feel of various anatomical landmarks, e.g., ligaments, and to recognize specific motor response to stimulation by applying pressure or electrical current or both to a needle once it is in the proximity of the desired location. This motor response is typically the movement of a small muscle group that manifests itself as movement of a particular part of the body e.g. flexing of the wrist. The magnitude of this movement is directly proportional to the amplitude of the electrical current at the needle tip and the proximity of the needle tip to the stimulated nerve.
Traditional training methods have required that the anesthetist learn these procedures by observation and by practicing the procedure directly on a live patient. The current training methods inevitably results in novice anesthetist error and resulting patient pain or injury.
It is accordingly a specific object of the present invention to provide a medical simulator which can be used to train anesthetists to perform regional anesthesia techniques with an enhanced degree of confidence and experience, particularly when first making the transition from theory to performing the first procedure on a live patient.
An increasing adverse medico-legal climate is making it mandatory for all practicing clinicians to ensure that they have undertaken the necessary practical training before undertaking invasion procedures clinically. It is accordingly a specific object of the present invention to provide a medical simulator which will assist in addressing the need for such training.
The present invention provides a medical simulator that comprises:
a) a simulation of a part of the human anatomy (e.g., shoulder and partial arm), called a mannequin, into which a needle or other penetrating instrument can be inserted;
b) a sensor system within said simulation part for sensing the position of the tip of the needle and any electrical current or property attributed to it; and
c) a display means for displaying a representation of said part of the human anatomy, movement of the tip of the needle and a display of any movement of other parts of the anatomy which result from any electrical current flow through the needle as sensed by the sensor means.
In general the instrument may be a needle, a scalpel, a trocar, a cannula, or a catheter, or any other medical instrument capable of penetrating the mannequin without destroying it. The simulation of the part of the human anatomy may include a replaceable simulated skin outer cover comprising a conductive elastomer, replaceable simulated muscle segments and a replaceable conductive elastomer element containing simulated nerves of conductive elastomer. Different thickness and characteristics of each of the elastomer elements (skin, muscle, nerves) may be provided so that the user can experience different degrees of difficulty in palpating and penetrating the anatomy proximal to the nerve. The simulation of the part of the human anatomy may also include a simulated circulatory system and elements such as an artery or vein, which may contain fluid.
The simulation of the nerve preferably includes a plurality of alternating conductive and insulating layers. The sensor means preferably comprises a network of electrical contacts at each conductive layer or element. Electrical contact with each of these independent layers by means of an electrically charged needle or implement will complete an electrical circuit so that needle location can be evaluated. Measurement of various electrical characteristics (e.g., resistance or capacitance) within the conductive layer can be used to provide additional information (e.g., relative position of contact within the layer or electrical current flow within the layer.)
According to a second aspect of the present invention there is provided a method of training a clinician in the carrying out of medical procedures which include the use of the medical simulator as defined above. The simulator is so designed as to provide a full range of both visual and tactile feedback, which is essential if the simulator is to fill the training vacuum, which currently exists.